This invention is concerned with a novel process for 5-methyl-10,11-dihydro-5H-dibenzo-[a,d]cyclohepten-5,10-imine, and its pharmaceutically acceptable salts which is useful as an anxiolytic, antidepressant, anticonvulsant, muscle relaxant, and in the treatment of mixed anxiety-depression, minimal brain dysfunction and extrapyramidal disorders such as Parkinson's disease.
The product of the novel process of this invention, 5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine and its enantiomers are known in the prior art such as Christy et al., J. Org. Chem.; 44, 3117-3127 (1979), South African Pat. No. 78/5291 and its West German counterpart Offenlegungschrift 28 40786. The best process known for synthesis of the racemate consists of nine steps from 5-H-dibenzo[a,d]cyclohepten-5-one with an overall yield of about 23%. Another process disclosed in EP published Application 0019866 prepares the compound in 5 steps with an overall yield of about 4% of theoretical.
Now, with the present invention, there is provided a novel process consisting of four steps from 5H-dibenzo[a,d]cyclohepten-5-one with an overall yield of about 64%.